Sudoku Game Two Levels of Difficulty

Printed-grid logic drives Sudoku Game Two Levels of Difficulty, a newspaper-style number puzzle with nearly 50,000 unique boards. Every grid has a single valid answer. Two modes divide the set into easy and difficult, with the first showing more digits from the opening layout and the second leaving much more of the board blank.

How to play?

Fill the 81-cell square by placing digits in the empty spaces. Rows block repeats of the same number, and columns follow the same rule. Each 3x3 box also needs the digits 1 through 9 with no duplicates. Given numbers fix the layout from the first move, shaping the rest of the puzzle. Hard mode leaves fewer clues on the grid. Careful checking of each box and every number helps avoid dead ends, since only one arrangement solves each board.